Air Exchanger and Brushes

Since doing a little cutting on the KRMx01 and having a lot more to do just to finish the dragon cables, I thought it would be a good idea to try to combat some of the dust created by the process.

The Air Exchanger

Kronos robotics sells an air exchanger that, while allowing the cooling air generated by the router to cool the bearings, directs the air away from the router so that it isn't blowing the dust around. This little add-on coupled with a brush of the right length will allow you to capture 99% of the dust generated according to the creator Michael Simpson. Pictured to the left is the exchanger I purchased from Kronos Robotics for my Hitachi Router. Sorry about the picture, there is some dust on it since I have been cutting with it.

Parts Needed for the Shrouds and Brushes

Pictured to the left is all the stuff needed to make a shroud and brush assembly for the air exchanger. If you buy the exchanger, Michael has the drawings, G-Code and assembly instructions available for this project on his website at kronosrobotics.com. Here you see the shroud pieces that I have already cut out on my machine, the craft foam (the parts are sitting on), the screws, lock washers and nuts.

Cutting the Plastic Shroud Pieces

Cutting the upper and lower shroud pieces turned out to be something of a challenge. The default feed in the G-Code is 50 IPM and Mr. Simpson suggests running the router at about 10,000 RPM. So I set my Hitachi router to about the third way mark on the speed control and let it fly. The job seemed to be okay at first but as it went along, I started noticing a little melting of the plastic. I tried changing the speed of the router up but was not really sure if I was having an effect or not. The image to the left shows the parts that I cut and if you look close you will see little divots here and there where the plastic melted. Now in fairness to Mr. Simpson, he told me when asking a question about what plastic do I need to buy for the limit switches, that the Home Depot / Lowes acrylic plastic did not machine well. I think though, that with the combination of bit, speed and feed that this stuff should be millable. When I have the SuperPID installed, I plan on doing a little experimenting to see if I can produce better plastic parts. After all, I will need a couple more sets of these shrouds.

Making the Brushes

The brushes are made from strips of craft foam. This stuff can be purchased at Walmart and other stores. It is cheap and very easy to work with. I started by measuring and cutting the little bristles with an Exacto knife. Then I quit measuring them and just started cutting them with an Exacto knife and a straight edge. Finally, I decided it was so tedious that I just grabbed a pair of scissors and just cut them to about an 1/8 inch wide. Let me restate that, cutting these things out kinda sucks, it is slow business, even just eye balling it and using scissors to cut them. If I wasn't so cheap, maybe it would be better to just order them from Kronos Robotics and save yourself the headache. On the upside, I did get a chance to catch up on some news while doing it. Anyway, here they are, three short brushed cut and ready to be glued to the shroud.

Assembling the Shroud

Tapping the plastic and assembling was pretty straight forward. The only part I was unsure of was the bottom piece of the shroud. I was not sure if it was supposed to be tapped or the screws just force threaded into it. I clamped the two pieces and tapped them through. The first image shows the completed shroud and the second with the shroud attached to the air exchanger.

Gluing the Brushes

What can you say about gluing the brushes on? Actually my son Zachary was nice enough to glue the brushes on the shroud while I had lunch. Thanks Zach. The image on the left shows the completed brush assembly and the one on the right shows it attached to the air exchanger.

Putting it all together

Here you see the air exchanger attached to the router and in the next two images the brush is attached. Now to cut some stuff and see how much the dust and debris is reduced. Thanks for reading this page!